This invention relates to a dental appliance and, more specifically, to a dental prophylaxis angle (commonly called a "prophy angle").
Dental prophy angles typically include a hollow head on the end of a tubular body. One such angle is disclosed in Kraenzle U.S. Pat. No. Re 34,997. A drive shaft within the body drives a rotor in the head of the angle. At the rearward end of the angle, i.e., the end remote from the head, the drive shaft is driven by a drive mechanism. A prophylaxis cup ("prophy cup") is attached to the rotor. These angles are commonly constructed of lightweight, inexpensive plastic so that they are disposable and may be discarded after use, thus obviating the expense and inconvenience of sterilization. Inexpensive plastic materials do not lend themselves easily to use in connection with an angle which is sturdy and easily assembled and which operates smoothly and consistently. Designers of plastic prophy angles are continuously trying to improve such angles to make them more sturdy, operate more smoothly, operate with less friction, and to improve efficacy for cleaning and polishing teeth.